While I'm changing the thermostat on my truck I think I'd like to switch to a 6 blade clutch fan. I currently have a smaller, under 18", 5 blade mechanical fan. I've found what I think will work, Flex A Lite 5719, 19" clutch fan blade. I'm not sure which fan clutch to use though. Are any of you guys running a fan clutch and what type/part number. This is for a 390.

I've been reading some post on here and one guy stated that you need to run a smaller pulley when using a fan clutch. He said the stock mechanical fan has a 7.5" diameter pulley and you need a 6" dia. with a clutch fan. Not sure why.

What is everyone's experience with a clutch fan?

What did these trucks use for a fan from the factory with a 390 and A/C?

 

In order to use a fan clutch w/a FoMoCo fan, the fan must have a 2 3/8" diameter center hole.

C6MY-8600-A .. 7 Blade Fan - Use with Fan Clutch & A/C / Marked: C6ME-A or D0AE-C or D1AE-BA / 19 1/2" diameter with 2 3/8" diameter center hole / Obsolete

1968/69 F100/350 360/390 // 1966/71 Galaxie/LTD/Mercury 352/390/410/428 / 1968/73 LTD/Mercury 429 / 1973/78 LTD/Mercury/Lincoln Town Car 460.
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C4SZ-8A616-B .. Fan Clutch (Motorcraft YB-94) / Obsolete

1968/69 F100/350 240/300/360/390 / 1969 F100 302 // 1964/66 Thunderbird 390/428 / 1964/71 Galaxie/LTD/Mercury 352/390/410/428.
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D0TZ-8600-C .. 5 Blade Fan - Not used with Fan Clutch - Use with A/C / Marked D0TA-F / 19 1/2" diameter with 5/8" diameter center hole / Obsolete

1970/76 F100/350 360/390.

Do not buy a used fan until you thoroughly inspect it, once it's off the vehicle. Minute cracks can develop between the 4 mounting holes and the center hole.

 

Hi,

About 10 years ago I replaced the fixed 5-blade fan on my truck with a 7-blade fan/clutch assembly I got off of E-bay. It was advertised as coming off of a 1966 Merc with a 410.

Before installing, I replaced the clutch with a new unit from the local autoparts store. I didn't change the pully, used the same ole one.

Never had a problem with it. I pulled my 23ft RV trailer over a 6k foot pass many times over the past 10yrs.

Earliar this year I traded the 23ft in on a 26ft RV with a slide-out. It's 1500lbs heavier. I had over-heat problems on my first trip with it over the Pass. Upon inspection I discovered that the thermostatic "spring" and valve on the front of the clutch were frozen from rust.

I replaced the clutch under "life-time" warrentee. Clutch was defective and I had over-heat problems again.

Replaced this new clutch with another new one...... which was also defective, which I also almost over-heated on the Pass from. So,.... long story short..... I went back to the fixed 5 blade because, .... it will never fail me when going up a two lane, 6k foot pass in the middle of nowhere.

PS. I have heard nothing but horror stories concerning "flex" fan blades. They get metal fatague from flexing and eventually fail which pokes holes in yer hood, or radiator, or .....

 

Thanks, the fan from Flex A Lite I plan to use is a traditional blade, not a flex. I tried one of those years ago, never again.